Photographic color element with novel cyan dye



United States Patent 3,038,302 PHOTOGRAPHIC CGLGR ELEMENT WITH NilBVEL CYAN DYE Ernst Keller, Peter Hinder-mania, and Jean-Pierre Jung,

Basel, Switzerland, assignors, by mesne assignments,

to Ilford Limit-ed, Ilford, England, a company of Great Britain No Drawing. Griginai application Apr. 14, 1958, Ser- No. 728,065, now Patent No. 3,002,964, dated Oct.

3, 1961. Divided and this application Mar. 20, 1959,

Ser. No. 8%,639 Claims priority, application Great Britain Apr. 29, E957 This invention relates to colour photography and particularly to the silver-dye bleach process of colour photography.

This important method of producing colour records is based on the following general procedure. A photo graphic silver halide emulsion layer, usually a gelatino silver halide emulsion layer, includes as a uniform dispersion therein, a suitable dyestufi. The layer is exposed to light or otherwise rendered developable so that a latent silver image is formed therein. This image is developed to a silver image. The layer is then treated with a bleach bath which has the effect of oxidising the silver image and simultaneously reducing (or bleaching) the dyestuff in the region of the silver image. The silver salts and any residual silver are then removed from the layer and the layer then contains only a dyestufi image which is complementary in sign to the original silver image.

Considerable variations are possible in this process. For example, the layer may be dyed with the dyestuff after the exposure step or after the development of the silver image. Moreover, the dyestulf may be included in a plain gelatin layer coated adjacent to the emulsion layer. A large number of patents have been granted in respect of the process, the main details of which can be ascertained from British patent specifications Nos. 397,159 and 397,188.

In order to produce a record in full colour there is generally employed a multilayer material which contains three light-sensitive silver halide emulsion layers, one sensitive to blue light only and the others sensitised to green and red light respectively. To avoid these latter layers from recording blue light in addition to the light to which they are sensitised, it is usual to provide a blue-absorbing filter layer between these latter layers and the emulsion which is sensitive only to blue, a common form of assembly being:

(a) Support layer ([2) Red-sensitive emulsion layer (c) Green-sensitive emulsion layer (a!) Blue-absorbing filter layer (2) Blue-sensitive emulsion layer Layer (d) is not always essential since layer (e), when dyed yellow, may provide a sufficient barrier to blue light.

Polychromatic light incident on layer (e) causes the formation of latent silver images in layers (e), (e) and (b), respectively recording in those layers the blue, green and red sensations of the exposing light.

In the silver-dye-bleach process as ordinarily practised, layer (b) is dyed blue-green (cyan), layer (0) is dyed magenta and layer (e) is dyed yellow. Accordingly, when the material is exposed, developed to form silver images and subjected to the required bleaching treatment and treated to remove residual silver salts and silver, the final product carries positive yellow, magenta and cyan images complementary to the negative silver images formed on development, so that when viewed it provides an accurate representation of the original subject of the exposure.

One of the principal difiiculties in the silver-dye-bleach process is the selection of suitable dyestuffs for the purpose. Some hundreds of dyestuffs have been suggested, but most of the dyestufifs proposed are unsatisfactory in one or more respects. A principal difiiculty is to ensure that the dyestufi employed will not difliuse from the gelatin emulsion layer in which it is incorporated, and various proposals, such as mordanting, have been made to overcome this dilficulty. In selecting dyestuffs for use, moreover, it is desirable that they should be bleached rapidly by the bleaching baths employed and also preferable that their inclusion in the emulsion layer should not too seriously reduce the sensitivity of the emulsion. In addition, of course, it is desirable that the dye should approach as closely as possible to the theoretical requirement that, of red, blue and green light it should absorb all of one while fully transmitting or reflecting both of the others.

It is a particular difficulty when using disazo dyes that the bleaching tends to occur by breakdown at one of the azo groups preferentially, resulting in a variation in hue according to the extent of the bleaching. It is important for their use in colour photography that the hue should be unchanged at difierent levels of bleaching.

The present invention is concerned with the provision of a new class of cyan dyestuffs for use in the silver-dyebleach process, which approach more closely to the desiderata set forth above.

According to the present invention a process for the production of a cyan dyestuff image in a photographic layer comprises including in a light-sensitive gelatino silver halide emulsion layer, or in a plain gelatin layer coated adjacent thereto, a cyan dyestufi of the formula:

said image, subjecting the developed silver image to treatment which bleaches or removes the silver image and simultaneously bleaches the dyestuif in situ therewith, and

removing any residual silver and silver salts from the product.

Methods for the production of the foregoing class of dyestuffs are exemplified later herein. In general terms they are prepared by diazotising a compound of the formula A--NH coupling this with the compound of the formula:

sons: diazotising the product and coupling it with a compound of the formula:

on X

(SOQEDn the techniques being those generally used in the production of disazo dyestuffs.

Further according to the invention a process of colour photography comprises a process as just set forth in which the said gelatino-silver-halide layer is sensitive to red light and constitutes one of the layers of a multilayer photographic material which further contains photographic emulsion layers sensitive to blue and green light respectively dyed with yellow and magenta dyestuffs, and the said cyan dyestuff is included in the said red-sensitive layer or in a plain gelatin layer coated adjacent thereto. More particularly the invention provides a process in which the said cyan-dyed layer is layer (b) of an assembly consisting of:

(a) Support layer (b) Red-sensitive emulsion layer dyed cyan (c) Green-sensitive emulsion layer dyed magenta (d) Blue-absorbing filter layer (e) Blue-sensitive emulsion layer dyed yellow optionally with plain colloid separating layers between some or all of the adjacent layers recited.

The invention further includes such light-sensitive materials employed in the aforesaid processes, and suitable for variants of those processes, which consist of or include a gelatino silver halide emulsion layer containing a cyan dyestufi as above set forth.

Preferred dyestuffs within the general formula given above are those in which R is a methyl or ethyl group and the sulphonic acid of the middle naphthalene ring is in the 6 or 7 (preferably the 6) position. One of the sulphonic acid groups in the right-hand naphthalene nucleus is preferably in the 4 or 6 position of that nucleus with respect to the 8-hydroxyl group and where a second sulphonic acid group is present it is preferably in the 2, 3 or 4 position depending on the position of the first sulphonic acid group. Preferred positions where two sulphonic acid groups are present are the 3:6 and 2:4 positions.

Specific dyestuffs which have been found to be of particular value as set forth in the examples which follow.

The bleaching of the cyan dyestuffs employed in this invention can be effected by any of the types of bleaching bath commonly employed in the silver-dye-bleach process.

The plain use of acid, e.g. hydrobromic or hydrochloric, is effective but is very slow. The inclusion of halide salts has an accelerative effect, but these bleaching baths are still slow. The inclusion of a solvent for silver halide such as thiourea or pyridine has a strongly accelerative effect, and this can be greatly increased by the inclusion of an accelerating substance or catalyst. In these connections reference may be made to British patent specifigatfns Nos. 397,159 and 490,451 for suitable bleaching The following example, which for simplicity is concerned only with the treatment of a single layer containing the cyan dyestuff, will serve to illustrate the invention.

EXAMPLE Preparation of the Dyestufis DYESTUFF N0. 1

O O O CwHMn) OCHa HO NH-COCH:

-N=N N=N (l) HOaS -SO3H 36.9 parts of 3-amino-4-phenoxybenzene-l-carboxylic acid n-decyl ester are dissolved at room temperature in 300 parts of alcohol. 40 parts of concentrated hydrochloric acid are added to the mixture and it is then cooled, whereupon the chlorohydrate precipitates. 40 parts of ice are added and it is diazotised at 05' with a concentrated aqueous solution of 6.9 parts of sodium nitrite. After stirring for 2 hours at 0-5 and decomposing a little excess nitrous acid, the pale yellowish coloured, clear diazo solution is poured within 2 hours into a suspension of 25.3 parts of 1-amino-2-methoxynaphthalene6-su1- phonic acid and 60 parts of sodium acetate in 500 parts of water and 500 parts of ice. This is performed at 0-5. The coupling occurs immediately and the colour changes to red. The whole is stirred for 6 hours at this temperature, the acid is then neutralised by the gradual addition of 32 parts of sodium carbonate and the precipitated dyestuif is filtered off under suction. It is washed in the suction filter with a 5% sodium chloride solution.

The brownish-red monazo dyestuff is dissolved at the boil in 4000 parts of hot water in the presence of 2 g. per litre of the condensation product of dodecyl alcohol and 20 mol of ethylene oxide as dispersing agent, 6.9 parts of sodium nitrite are added, the reaction mixture is cooled to 25 and 40 parts of concentrated hydrochloric acid are added. After stirring for 15 hours at 25-30" a little excess nitrous acid is decomposed with sulphamic acid. The brown-yellowish gelatinous diazo emulsion is then poured at 15-20 into a solution of 36.1 parts of 1-acetylamino-8-hydroxynaphthalene-3.-disulphonic acid and parts of sodium acetate in 1000' parts of water and 250 parts of pyridine. The coupling takes place immediately and the colour changes to cyan. Stirring is continued for 4 hours at the same temperature, 600 parts of potassium chloride are added and the dyestuif which precipitates is filtered off under suction. It is washed first with 500 parts of a solution consisting of 50 parts of pyridine, 25 parts of potassium chloride and 350 parts of water, then with 500 parts of pyridine and, finally, with 200 parts of acetone, after which it is dried at 80.

The dyestuif is a blue powder which dissolves in Water with a cyan colouration and in concentrated sulphuric acid with a blue colouration.

The 3-amino-4-phenoxybenzene-l-carboxylic acid decyl ester used as starting component is obtained by condensing 4-chloro-3-nitrobenzene-l-carboxylic acid with excess phenol in the presence of 2.2 mols of potassium hydroxide at temperatures of over C., isolating the free 4-phenoxy-3-nitrobenzene-l-carboxylic acid, converting this with thionyl chloride into carboxylic acid chloride, reacting the chlorid with n-decyl alcohol to form the decyl ester and finally reducing the nitro group to the amino group in aqueous ethyl alcohol.

The following table contains some further disazo dyestuffs which can be used and which can be produced by the method described above. If the starting components are homologous and isomeric or analogous compounds, they are also obtained by the method described above.

DYESTUFF NO. 2

0 CH3 HO NH:

SOaH

36.9 parts of 3-amino-4-phenoxy-l-carboxylic acid-ndecyl ester are diazotised as described in the example of Dyestuif No. 1 and coupled with 25.3 parts of l-amino-Z- methoxynaphthalene-6-sulphonic acid. This brown-red ride, filtered off and washed with saturated salt solution. monoazo dyestuif is dissolved in 4000 parts of boiling The diazo compound is pasted in 1000 parts of ice Water water in the presence of 2 g. per litre of the condensation and the suspension is added in portions at l520 C. to a product from 1 mol of dodecyl alcohol and 20 mols of solution of 31.9 parts of 1-amino-8-hydroxynaphthaleneethylene oxide as dispersing agent, 6.9 parts of sodium, 5 3.6-disulphonic acid and 40 parts of sodium acetate in nitrite are added, the temperature is reduced to 25 C. and 1000 parts or water and 250 parts of pyridine. Coupling 40 parts of concentrated hydrochloric acid are added. occurs immediately and the colour changes to cyan. After After stirring for hours at -25 C. and decomposistirring for 4 hours at 15-20 C. 400 parts of potassium tion of a little excess nitrous acid, the brown-yellow diazo chloride are added to the dyestulf solution, it is heated to suspension is poured at 2025 into a solution of 31.9 10 40 C., the precipitated blue dyestufi is filtered ofl under parts of 1-amino-8-hydroxynaphthalene-3.d-disulphonic suction and washed first with 300 parts of a 20% sodium acid and 80 parts of sodium acetate in 1000 parts of water chloride solution, then with 300 parts of pyridine and and 250 parts of pyridine. Coupling occurs immediately finally with 200 parts of acetone. It is then dried in the and the colour changes to cyan. After stirring for 6 vacuum at 80 C.

hours at 10-15 C., 600 parts of potassium chloride are 15 The dyestuli is a blue powder which dissolves in water added, the dyestufi suspension is heated to 40 C. The With a cyan colouration and in concentrated sulphuric acid precipitated blue disazo dyestulf is filtered off under sucwith a blue colouration.

DYESTUFF NO. 4

OCHa HO NHa (i) HOsS 30211 0 son:

tion and washed first with a solution consisting of 50 parts 341 parts of 3-amino-6-phenoxybenzene-1-carboxylic of pyridine, parts of potassium chloride and 350 parts acid-n-octyl ester are diazotised as described in the exof Water, then with 500 parts of pyridine and finally with ample of Dyestufi No. 1 and coupled with l-amino-Z- 200 parts of acetone, after which the dyestuff is dried in methoxynaphthalene-6-sulphonic acid. The brown-red the vacuum at 70-80 C. monoazo dyestuff is dissolved in 4000 parts of boiling The dyestufl is a blue powder which dissolves in water water, 6.9 parts of sodium nitrite are added, the tem- With a cyan colouration and in concentrated sulphuric perature is reduced to 25C. and parts of concentrated acid with a deep blue colouration. 40 hydrochloric acid are added. After stirring for 20 hours DYESTUFF NO. 3

HO S SO H 27.7 parts of 4-aminobenzene-l-carboxylic acid-nand decomposing some excess nitrous acid, the precipitated decyl ester are suspended in 200 parts of Water and 30 diazo compound is filtered ofi under suction and Washed parts of hydrochloric acid and diazotised at 0-2 C. with with a 20% sodium chloride solution. The diazo com- 6.9 parts of sodium nitrite. The clear solution of the pound is then pasted in 1000 parts of ice water and this diazo compound is then poured at 0-5 C. gradually into suspension is added at 2025 C. in portions to a solution a suspension of 25.3 parts of 1-arnino-2-methoxynaphthaof 31.9 parts of l-amino-8-hydroxynaphthalene-3.6-disul- 1ene-6-sulphonic acid and 60 parts of sodium acetate in phonic acid and 40 parts of sodium acetate in 1000 parts 500 parts of water and 500 parts of ice. The coupling 7 of Water and 250 parts of pyridine. The coupling occurs occurs immediately and the colour changes to red. The immediately and the colour changes to cyan. After stir- Whole is stirred for 6 hours at 0-5 C., the acid is ring for 6 hours at 2025 C., 180 parts of potassium neutralised by the addition of 32 parts of sodium carchloride are added to the dyestuft" solution, it is heated bonate, the red dyestuif which precipitates is filtered off to 35 C. and the precipitated blue disazo dyestufi is under suction and Washed in the suction filter with a 5% filtered off under suction. It is Washed as described in sodium chloride solution. the example of Dyestufi No. l and dried at -80 in the The brown-red monoazo dyestuff is dissolved in 3000 vacuum. parts of boiling Water, 6.9 parts of sodium nitrite are 7 The dyestuft' is a blue powder which dissolves in water added, the solution is cooled to 25 C. and 40 parts of conwith a cyan colouration and in concentrated sulphuric centrated hydrochloric acid are added. After stirring for acid with a dark blue co louration,

20 hours at 2025 C., a little excess nitrous acid is de- The following table lists additional examples of dyes composed with sulphamic acid, the diazo compound is for use according to the invention. They conform to the precipitated by the addition of 750 parts of sodium chloformula:

T able'-Continued Position OfSOgH Dye A R X grup( No. inend component 22 O-oOoooommm can, NH. M

23 O-OQCOOCwHMD) -on.ooon NH,

2.33 gms. of dyestufi No. 1 above and 7.4 grns. of dodecyl sodium sulphate are dissolved in 460 cos. of OR 03 X water. This dye solution is then added to 740 cos. of a silver chlorobromide emulsion containing 2.6 gms. of A-N=N silver as silver halide. The mixture is then coated on 20 (303E),

film base to give a coating weight of 2.7 mgms. of silver per square decimeter.

The dried coating is exposed to light to record an image therein and processed at 6 8 F. as follows:

(1) Develop to a silver image by two minutes treatment in the following developer:

Metol .gms 0.75 Sodium sulphite, cryst gms 25 Hydroquinone gms 3 Sodium carbonate, cryst gms 40 Potassium bromide gms 1 Potassium bromide gms 12.5 Thiourea gms 1O 2:3-dimethyl quinoxaline gm 0.1 Water to 1 litre. (8) Wash minutes.

(9) Silver bleach for 5 minutes in the following bath: Copper sulphate, cryst g=ms 100 Sodium chloride gms 100 Hydrochloric acid, cone... ccs 50 Water to =1 litre. (10) Wash 5 minutes. (11) Fix in sodium thiosulphate for 3 minutes. (12) Wash for 10 minutes and dry.

A reverse image in dye is obtained.

Steps 4 and 5 may be omitted if the original emulsion is hardened or provided with a hardened gelatin supercoat.

Similar results are obtained using the other dyestufis falling within the formula stated, and particularly when using Dyestufis Nos. 2, 3 and 4 above. When the process is repeated with a similar, but undyed, silver halide emulsion, supercoated on the dyed emulsion, it is found by microscopic examination that substantially none of the dyestuff in the dyed layer migrates to the undyed layer either on coating the film or on processing.

All the said dyestufls are of satisfactory hue, have very good resistance to migration, bleach rapidly and effectively, and are generally of exceptional value in the silverdye-bleach process of colour photography.

This application is divided from application Serial No. 728,065, filed April 14, 1958, now Patent No. 3,002,964.

What we claim is:

l. A light-sensitive gelatino silver halide emulsion comprising a cyan dyestuif of the formula:

where A is a radical selected from the class consisting of phenyland phenoxyphenyl-carboxylic alkyl esters of which the alkyl group contains at least 5 carbon atoms, R is selected from the class consisting of alkyl groups containing up to 6 carbon atoms and carboxymethyl groups, X is selected from the class consisting of hydroxy, amino, alkyl carbonylamino, phenylalkyl carbonylamido, phenyl carbonylamido, haloalkyl carbonylamido, halophenyl-alkyl carbonylamido, halophenyl carbonylamido and halophenoXy-alkyl carbonylamido groups, and n is an integer at least 1 and not more than 2..

2. A multilayer photographic material comprising a layer of gelatino silver halide emulsion containing a cyan dye and sensitive to red light, a layer of gelatino silver halide emulsion containing a yellow dye and sensitive to blue light, and a layer of a gelatino silver halide emulsion containing a magenta dye and sensitive to green light, wherein the cyan dye is of the formula:

where A is a radical selected from the class consisting of phenyland phenoxyphenyl-carboxylic alkyl esters of which the alkyl group contains at least 5 carbon atoms, R is selected from the class consisting of alkyl groups containing up to 6 carbon atoms and carboxymethyl groups, X is selected from the class consisting of hydroxy, amino, alkyl carbonylamido, phenylalkyl carbonylamido, phenyl carbonylamido, haloal kyl carbonylamido, halophenyl-alkyl carbonylamido, halophenyl carbonylamido and halophenoXy-alkyl carbonylamido groups, and n is an integer at least 1 and not more than 2.

3. A multilayer photographic material comprising an assembly consisting of:

(a) support layer (b) red-sensitive emulsion layer dyed cyan (c) green-sensitive emulsion layer dyed magenta (d) blue-absorbing filter layer (e) blue-sensitive emulsion layer dyed yellow the cyan dye in layer (b) being a dyestufi of the formula:

SO H

1 1 where A is a radical selected from the class consisting of phenyland phenoxyphenyl-carboxylic alkyl esters of which the alkyl group contains at least 5 carbon atoms, R is selected from the class consisting of alkyl groups containing up to 6 carbon atoms and carboxymethyl groups, X is selected from the class consisting of hydroxy, amino, alkyl carbonyl amido, phenylalkyl carbonylamido, phenyl carbonylamido, haloalkyl carbonylamido, halophenylalkyl carbonylamido, halophenyl carbonylamido and halophenoxy-alkyl carbonylamido groups, and n is an integer at least 1 and not more than 2.

.4. An emulsion according to claim 1 wherein the cyan dyestufi is:

0033:: H0 NH:

OCH: OH NH;

6. An emulsion according to claim 1 wherein the cyan l 2 dyestuff is:

('30 O Cn M 5 O 0 Hg 0 H NH;

N=N N=N-- (l) H O as S 0 all 1 O 3 311 7. An emulsion according to claim 1 wherein the cyan dyestuff is:

(3 O O C6H1l(Il) (I) O H; OH NH;

-N=N N'=N O 110 s S 0 11 0 H (tert.)

8. An emulsion according to claim 1 wherein the cyan dyestufi" is:

(lJOOCs zK O OCHa 0H NH:

--N=N N=N (I) HOaS- -SO3H References Cited in the file of this patent UNITED STATES PATENTS 1,880,572 Wendt et a1 Oct. 4, 1932 2,694,636 Keller Nov. 16, 1954 FOREIGN PATENTS 298,979 Great Britain Feb. 20, 1930 

2. A MULTILAYER PHOTOGRAPHIC MATERIAL COMPRISING A LAYER OF GELATINO SILVER HALIDE EMULSION CONTAINING A CYANDYE AND SENSITIVE TO RED LIGHT, A LAYER OF GELATINO SILVER HALIDE EMULSION CONTAINING A YELLOW DYE AND SENSITIVE TO BLUE LIGHT, AND A LAYER OF A GELATINO SILVER HALIDE EMULSION CONTAINING A MAGENTA DYE AND SENSITIVE TO GREEN LIGHT, WHEREIN THE CYAN DYE IS OF THE FORMULA: 